Almost 10,000 first responders training at Anniston's Center for Domestic Preparedness in Alabama unknowingly trained with a toxic form of ricin over the last four years, reports AL.com .

That's according to officials with the Federal Emergency Management Agency, who said no CDP personnel or students were harmed to their knowledge during that time.

Lisa Hunter, a spokeswoman for the CDP, said the center began training with ricin in February 2012, and 9,648 students used the toxic form during that time without their knowledge.

The CDP trains emergency responders from across the nation in responding to chemical, radiological, and biological events through the Department of Homeland Security. The training deals with natural disasters as well as possible acts of terrorism.

On the center's website, for example, it bills the work at the Chemical Ordnance Biological and Radiological Training Facility as "the only program in the nation featuring civilian training exercises in a true toxic environment, using chemical agents and biological materials.

"The CDP recently discovered that due to an error by the supplier of the biological material ricin, the CDP received the toxic form of the material, ricin holotoxin, and not the much less toxic, ricin A-chain, as ordered," Hunter said in a series of responses to questions submitted by AL.com.

"The CDP staff adhere to strict protocols and procedures for handling and training with the biological materials that meet or exceed the Centers for Disease Control and Prevention's requirements for safe storage, handling and use of...ricin," she said. "As a result, no CDP personnel or students were harmed by any toxins used at the CDP."

The use of the toxic ricin was discovered during communications between a CDP employee and the vendor, Hunter said. CDP officials declined to publicly identify the vendor, but have stopped using it, she said.

As a result of the discovery, officials have begun internal and external reviews of the center's safety precautions.